1. Field of the Invention
The present invention relates to a data processing system for a sewing machine and, more particularly, to a data processing system which enables a plurality of selected characters such as letters or symbols to be stitched on a material along a desired curve.
2. Description of the Prior Art
The embroidery of stitching characters such as letters or symbols on work fabric by a sewing machine is well known in the art, as has been proposed U.S. Pat. Nos. 4,413,574, 4,309,950 and 4,352,334, for example. In the embroidery disclosed, the operator first selects the characters to be stitched. In accordance with this selection, the machine control system reads out the pattern data of the selected character from the pattern data which are stored in advance in a memory, and moves work fabric holding means and a needle relative to each other in accordance with the read-out pattern data to stitch the selected character on the work fabric.
In the U.S. Pat. No. 4,413,574, more specifically, there is disclosed an automatic sewing machine in which the pattern data of a character are stored in a predetermined form in a memory and used to magnify or reduce the sizes of the individual characters or to arrange the characters along a predetermined straight line and stitch them on the work fabric. In the sewing machine disclosed in the U.S. Pat. No. 4,309,950, on the other hand, a desired stitch pattern can be shared and formed symmetrically with respect to a predetermined point. The prior art of determining the position of the characters to be stitched is disclosed in the in U.S. Pat. No. 4,352,334 which was assigned to Merco Industries Incorporated. What is disclosed by this patent is merely to stitch the characters along a predetermined arc. And, the operator has to select a diameter of the arc.
As described above, the device of that patent can stitch the characters along a selected arc but not along a variable curve. This raises a problem that the application of the resultant embroidery is limited.
In the U.S. Pat. No. 4,444,135, on the other hand, there is disclosed not an invention relating to the sewing machine but a program system for forming stitches along such a variable curve as can be selected by the worker. This program system cannot make the program of a stitch pattern along the aforementioned curve.